Added functions match_remove/1,3,4 to all metrics

[RoadRunnr]

match_remove can be used to selectively remove values for multiple labels. The match head and match condition use the same rules as the match specification parts of the same name.

This similar to #108, but can use arbitrary match conditions to select which labels to remove.

[RoadRunnr]

@deadtrickster can you take a look, please?

[mgumz]

@deadtrickster ping